The present invention relates to the field of vacuum generators that use Venturi valves. More particularly, the present invention relates to the field of controlled vacuum generators that include feedback for maintaining the operating mode or function of the vacuum generator in the event of an emergency stop condition or if electrical power is lost.
It is an object of the present invention to provide a pressure feedback circuit for controlling the output of vacuum pressure generator.
It is an object of the present invention to provide a pressure feedback circuit for controlling a vacuum pressure generator in the event of emergency conditions that preclude the use of electrical power to control the vacuum pressure generator.
It is an object of the present invention to provide a pressure feedback circuit to maintain the same state of output pressure for a vacuum pressure generator in the event of an emergency condition or loss of electrical power.
The present invention is a pressure feedback circuit for use with a vacuum pressure control circuit. The vacuum pressure control circuit comprises a pressure controlled valve to control the application of an independent pressure source to a vacuum pressure generator thereby generating vacuum pressure at an output vacuum pressure port. The vacuum pressure control circuit controls the generation of vacuum pressure under normal operating conditions.
The pressure feedback circuit detects the occurrence of, and controls the generation of vacuum pressure under, External Override Conditions (xe2x80x9cEOCsxe2x80x9d). During EOCs, which typically include emergency stop conditions or loss of electrical power to the vacuum pressure circuit, the pressure feedback circuit senses the condition of the output vacuum pressure port and supplies pressure feedback to the vacuum pressure control circuit thereby maintaining the last output state of the vacuum pressure control circuit.
The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its structure and its operation together with the additional object and advantages thereof will best be understood from the following description of the preferred embodiment of the present invention when read in conjunction with the accompanying drawings. Unless specifically noted, it is intended that the words and phrases in the specification and claims be given the ordinary and accustomed meaning to those of ordinary skill in the applicable art or arts. If any other meaning is intended, the specification will specifically state that a special meaning is being applied to a word or phrase. Likewise, the use of the words xe2x80x9cfunctionxe2x80x9d or xe2x80x9cmeansxe2x80x9d in the Description of Preferred Embodiments is not intended to indicate a desire to invoke the special provision of 35 U.S.C. xc2xa7112, paragraph 6 to define the invention. To the contrary, if the provisions of 35 U.S.C. xc2xa7112, paragraph 6, are sought to be invoked to define the invention(s), the claims will specifically state the phrases xe2x80x9cmeans forxe2x80x9d or xe2x80x9cstep forxe2x80x9d and a function, without also reciting in such phrases any structure, material, or act in support of the function. Even when the claims recite a xe2x80x9cmeans forxe2x80x9d or xe2x80x9cstep forxe2x80x9d performing a function, if they also recite any structure, material or acts in support of that means of step, then the intention is not to invoke the provisions of 35 U.S.C. xc2xa7112, paragraph 6. Moreover, even if the provisions of 35 U.S.C. xc2xa7112, paragraph 6, are invoked to define the inventions, it is intended that the inventions not be limited only to the specific structure, material or acts that are described in the preferred embodiments, but in addition, include any and all structures, materials or acts that perform the claimed function, along with any and all known or later-developed equivalent structures, materials or acts for performing the claimed function.